Quad amp choice

[admin_exported]

Hi people,

Im looking for a power amp to match my quad preamp, and I could really use some advise. My speakers are Epos M12.2 which are 87db and 8ohms. There are three options I’m considering and I’m not sure what would provide the best sound quality;

1./ The Quad stereo 909 power amp (140 watts)

2./ Two Quad 99 stereo amps in a bi amp configuration (80 watts each)

3./ A pair of Quad monoblocks (150 watts each)

Any advise would be much appreciated : )

 

[lordmortlock]

Morning Quantum.

If it were me I'd go for a 909 power. Mines plenty loud enough for my needs and it sounds lovely. You can always add another one and bi amp later if needed

 

[Anonymous]

I bought a used Quad 405 and had it converted and upgraded by Netaudio to the MK3 level with better op amps. For a grand spend of £500 it sounds very good indeed. I also bought a used AVI S2000MP for £150 which seems to be very transparent and works well. It really is possible to get superb hifi for less cash!

 

[Frank Harvey]

The 99 will power your Epos just fine, but there's quite a difference between the 99 and 909. That's the one I'd be aiming for.

Monoblocks will give you certain benefits over a stereo power amp. The imaging will be improved due to the channel separation. Obviously power benefits too, not that I think you'd need it anyway. Going for the mono's will be beneficial for qiality, but also if you're looking at changing speakers at some point - if you upgrade the speakers, you pretty much have the choice of anything......which is nice

 

[Anonymous]

Hi

I own Quad 909 and 99 Quad Stereo Amp's

I would go agree and say get the Quad 909 and when convenient get another one later, to bi-amp. This is actually what im planning on doing, after ive got myself a decent pre-amp, with two pre-out's.

The step up from the Quad 909, i found to be quite dramatic, much bigger difference than i was expecting0. When going back to listening to the Quad 99 in my opinion the Speakers sound out of control.

I think with your speakers would perform much better with the extra controlled muscle of the Quad 909.

Summary: Quad 909, to start then upgrade to bi-amp configuration. Purchasing another Quad 909 later.

Regards

 

[MUSICRAFT]

Hi quantum

I agree with c_m. Start with one 909 and tthan take it from there.

Thanks

Rick @ Musicraft

 

[Anonymous]

Thanks for the great replies people!

I want to get it right the first time so i dont have to upgrade later. Its a tough desision, because the 909 has such a great reputation with its current dumping technology ect, but some people would swear that biamping to average quality amps (such as using two 99 powers) would beat one very high quality amp (such as the 909).

Then there are the mono amps which i dont know much about. All things being equal are mono amps meant to be better than a stereo amp?

Duh so confusing!

 

[Anonymous]

Hi Quantum

hmm.. I agree this is a difficult one.

I however still now find the difference in dynamics and control and musicality, so much of an improvement.

Im not an Engineer by any means, but the Quad 909 internally has been described as being like a two amplifier system, hehe because there is a smaller amplifier for ensuring the output is correct then another that provides the muscle. But mainly the step up i think is very big and from what i have seen you can get better deals on a Quad 909 than the Quad 99, as far as percentage off RRP goes if you catch my drift.

Specifically for use with your speakers i would using a single Quad 909. You would probably also save yourself a fair bit of money.

I don't know whether your able to, but you could try and get a Home Demo using 2 x Quad 99 vs 909. I don't know whether that would be asking to much or not of a Hi-Fi Dealer, these days.

Regards

 

[Anonymous]

The 909 uses Quad's patented current dumping technology which basically means that there's a very high quality, low power class A amp with a large dump amp. My 405 is 30W class A with 70W dump. This gives the benefits of the sweet, fluid and detailed sound of class A where most of the music is amplified, with the benefits of having lots of dynamic headroom to cope with peaks in music. Further, the design does not need biasing so will not degrade in quality due to bias drift.

The 99 amp is of the more traditional class AB topology so does not have the same benefits, albeit it's still a very good amp. Also I believe they are biased as with most amps, something that will drift in time.

Go for the 909, you won't look back. Get a decent pre, at the very least the matching Quad 99. I've had a dealer try to persuade me that the 909 powerhouse has no finesse; rubbish. It's a stunning amp following on the same design topology of the late sixties early seventies.

I use a fully rebuilt and upgraded 405 and it sounds breathtaking. It just goes to show how good the design is.

 

[Anonymous]

Im not sure what bias shift is, but it sounds like some kind of degradation that occurs in an amp over time. If the 909 isnt effected by this than thats a bonus, i wonder if the monoblocks are susseptible to bias shift? Two monoblocks actually cost the same as the retail for the 909 amp so its a hard one to call. I dont think the mono amps utilise the same current dumping technology as the 909, but there are numerous arguments supporting the idea of monoblocks. At the end of the day i think im still leaning towards the 909.

I wonder how the 909 would sound when connected to a passive pre amp such as the Creek OBH-22?

 

[Anonymous]

I was going to go the passive pre route (and may still for curiosity). The thing that put me off is other people seem to find that they sound a bit flat compared to an active pre. Active pres will indeed add something to the sound by way of distortion, but that's not always a bad thing. I've heard that a good active pre will give the sound more life and weight. It's worth an experiment!

 

[Anonymous]

igglebert what is bias shift?

 

[Anonymous]

Don't know I'm afraid, but the typical class A/B amp bias drift will be caused by aging components and the fact that the amp is biased at manufacture. This doesn't not happen on the 405 design.